Worcester Bosch Greenstar 4000 System fault 810

Hot water remains cold

Gas boiler

What it means

Fault indicating domestic hot water is not heating.

Likely causes

  1. Faulty DHW valves
  2. Faulty 3-way valve
  3. Tank not properly connected

Where to start

  1. Check the DHW valves
  2. Check the 3-way valve
  3. Check that the tank is properly connected

The full answer, free

  • How to put it right, step by step
  • The manual page for this fault (page 74), right under the answer

Safety: Isolate gas and power before you open the case. If you have been into the gas side, do a tightness test, and a combustion and flue check before you hand back. Gas Safe (UK) or RGI (Ireland) work only.

From the Worcester Bosch manual for the Greenstar 4000 System. Check the model on the data plate before you order parts.

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